System and method for transporting and sputter coating a substrate in a sputter deposition system

ABSTRACT

A substrate handling system auxiliary to a plasma sputtering system is described. The substrate handling system inserts an unprocessed substrate (e.g., an optical disk), an inner mask, and an outer mask into a loadlock of the sputtering system, and then seals the access opening to the loadlock. The substrate and the masks then are moved to a sputtering chamber where the substrate is coated by sputtering. Subsequently, the substrate handling system moves a processed substrate, and its accompanying inner mask and an outer mask, from the loadlock to an external disk change station, where the processed substrate is removed from the masks, which are still gripped by the substrate handling system. Subsequently, another unprocessed disk is placed on the inner mask and within the outer mask, and the sequence repeats. The substrate handling system only contacts the masks on surfaces thereof that are not subjected to direct sputter deposition, so that the masks can be gripped without causing particulate contamination. A coated surface of the inner mask and outer mask has numerous asperities to trap sputtered material and reduce contamination.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a divisional of U.S. patent application Ser.No. 09/547,522, which was filed on Apr. 12, 2000, and is incorporatedherein by reference in its entirety. This application also is related toU.S. patent application Ser. No. 09/547,986, which was filed on Apr. 12,2000, and is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

[0002] This invention relates generally to a system for loading andmasking substrates in association with a sputter deposition system.

BACKGROUND OF THE INVENTION

[0003] A conventional optical disk includes a plastic base upon whichlayers of various materials, such as metals, alloys, or dielectrics, areapplied. One method of applying the layers of materials is to use asputter deposition process.

[0004] A conventional sputter deposition process is performed using aplasma formed in a vacuum chamber of a sputter deposition system. Theplasma is generated by applying electric power to a low pressure gas inthe vacuum chamber. Ions originating within the plasma bombard a targetformed of a material that is to be deposited on the optical disk. Thebombarding ions eject material from the target. The ejected materialdeposits in a layer on the disk.

[0005] A conventional sputtering system known as the BALZERS™ BIGSPRINTER™ is believed to include a loadlock between a main vacuumchamber and a disk loader robot. The disk loader robot includes twoopposing arms, each of which includes an identical disk holder. Anexternal robot loads an unprocessed optical disk (or other substrate)into the disk holder, and unloads a processed disk from the disk holder.The disk loader robot rotates 180°, and thereby alternatively positionseach disk holder at the loadlock and the external robot.

[0006] During the sputtering operation, the two masks, one known as aninner mask and one as an outer mask, prevent deposition on the centraland peripheral portions of the disk, respectively. The inner maskconsists of a solid cylindrical body with an annular head attached toone end of the cylindrical body. At the outside of the cylindrical bodyis a spring mechanism that traps the disk under the annular head. Theouter mask is in shape of a flat ring. The disk holders and the carrierarm hold the masks using magnets. The annular head of the inner mask andthe surface of the outer mask that faces in the same direction as thesputtered surface of the disk both get a coating of the sputteredmaterial. Magnetized components of the disk holder and the carrier armcontact the sputtered surfaces of the inner and outer masks duringloading and handling processes.

[0007] The sputter-coated inner and outer masks need to be replacedperiodically. To do this, the disk loader robot is rotated 90°, therebyplacing the disk holder with the masks that are to be replaced at astation dedicated to changing of the masks.

[0008] There are drawbacks to the above described system that heretoforehave not been resolved. First, contacting the sputtered surfaces of theinner and outer masks dislodges sputtered material from the masks,causing particulate contamination on the disk and in the sputteringsystem. Second, the masks get hot in the vacuum chamber, and havelimited opportunities to cool. The hot masks can cause heat damage tothe surface of the disk. Third, the use of magnets near the substrate tohold the masks affects the plasma, thereby affecting the uniformity ofthe film. Fourth, the sputtering system includes a station dedicated tochanging of the masks, which consumes valuable space in the machine.

SUMMARY OF THE INVENTION

[0009] The present invention overcomes the aforesaid shortcomings of theprior art, while at the same time providing a high throughput andreliable system for loading, unloading, handling, and maskingsubstrates, such as optical disks, that are to be coated with asputtered material. The surfaces of the masks that are subjected todirect sputter deposition (i.e., the surfaces that face in the samedirection as the coated surface of the substrate) are not handled, whichavoids the particulate contamination seen in the prior art system.

[0010] A sputtering system within the present invention includes asubstrate handling system. The substrate handling assembly movesindividual unprocessed disks (i.e., disks to be sputter coated) betweena disk change station, which is external to the sputtering system, and aloadlock of the sputtering system. The substrate handling assembly movesindividual processed disks (i.e., coated disks) between the loadlock andthe disk change station. An inner mask and an outer mask accompany eachunprocessed disk from the external disk change station, through thesputtering system, and back to the disk change station.

[0011] The substrate handling system includes one or more arms. At theend of each arm is a disk and mask handling assembly, which is called an“end effector” herein. In one embodiment, the end effector comprises alid that fits over an access opening to the loadlock. The end effectoralso includes an inner mask gripper and an outer mask gripper. The innermask gripper grips the inner mask, and the outer mask gripper grips theouter mask.

[0012] The inner mask is generally mushroom shaped and fits in a hole inthe center portion of the disk. Unlike the prior art inner mask,however, the inner mask of the present invention has a centralcylindrical opening that is accessed through the annular head. The innermask gripper grips the inner mask on a sidewall surface within thecylindrical opening that is not subjected to direct sputter deposition.

[0013] The outer mask has a hollow vertically-extending body with acentral opening that is sized so that a disk can be horizontallydisposed within the central opening. A lip at the top of the bodysuperimposes a circumferential portion of the disk. The outer maskgripper grips the outer mask on an outer surface of avertically-extending sidewall of the body of the outer mask. The grippedsurface is not subjected to direct sputter deposition.

[0014] In one embodiment, the substrate handling system operates bypositioning an end effector that is gripping an inner mask and an outermask at the external disk change station. An unprocessed disk is placedand centered on the inner mask and within outer mask. The substratehandling system moves the end effector to the loadlock, places theunprocessed disk and masks into the loadlock, and seals the accessopening to the loadlock with the lid. The end effector pushes the innermask and outer mask onto a substrate transfer tray positioned in theloadlock. The masks are released by the end effector. The disk and itsaccompanying inner and outer masks then move on the tray to a sputteringstation. Subsequently, after a tray having a processed disk and innerand outer masks is moved into the loadlock, the load lock is vented, andthe end effector at the loadlock grips the inner and outer masks onunsputtered surfaces thereof, thereby capturing the processed disk. Thesubstrate handling system moves the end effector to the disk changestation, where the processed disk is removed from the inner and outermasks. The cycle subsequently repeats. The design of the system allowshigh throughput loading and unloading of the disks.

[0015] Further features and advantages of the invention will becomeapparent in view of the drawings and detailed description of theexemplary embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016]FIG. 1 is a cross-sectional side view of a substrate handlingsystem mounted on a sputtering system.

[0017]FIG. 2 is a simplified top plan view an alternative substratehandling system having three arms.

[0018]FIG. 3 is a cross-sectional side view of an inner mask.

[0019]FIG. 4 is a cross-sectional side view of an alternative innermask.

[0020]FIG. 5 is a cross-sectional side view of an outer mask.

[0021]FIG. 6 is a cross-sectional side view of an alternative outermask.

[0022]FIG. 7 is a cross-sectional side view of an end effector.

[0023]FIG. 8 is a perspective view of a rotary actuated outer maskgripper.

[0024]FIG. 9A is a simplified top plan view of an end effector havingfour rotary actuated outer mask grippers.

[0025]FIG. 9B is a simplified top plan view of an end effector havingone rotary actuated outer mask gripper and a belt.

[0026]FIG. 10 is a cross-sectional side view of a portion of analternative outer mask gripper for use with an outer mask.

[0027]FIG. 11 is a cross-sectional side view of an end effector havingan alternative outer mask gripper.

[0028]FIGS. 12a-12 f are cross-sectional side views of stages in theoperation of substrate handling system.

DETAILED DESCRIPTION

[0029]FIG. 1 illustrates portions of an embodiment of a sputteringsystem within the present invention. Sputtering system 20 sputterslayers of material onto the surface of a substrate using a plasma formedin each of several sequential sputtering stations. The disks and theiraccompanying inner and outer masks move from station to station on acarousel. In the example embodiments described herein, the substrate isan optical disk, but the type of substrate may vary. Other features thatmay be part of sputtering system 20 are disclosed in a commonly-assignedco-pending U.S. patent application entitled “Magnetic Array forSputtering System,” Ser. No. 09/499,092, which was filed on Feb. 4,2000, and is incorporated herein by reference in its entirety.

[0030] Sputter system 20 includes a loadlock 24 that is used for loadingand unloading optical disks. A substrate handling system 21 is mountedto sputtering system 20 adjacent to loadlock 24. In this embodiment,substrate handling system 21 includes two opposing arms 26 on a shaft 23that rotates and moves vertically. The number of arms can vary, however,as is discussed below. Handling system 21 loads unprocessed disks intoloadlock 24 and unloads processed disks from loadlock 24 through accessopening 24A in loadlock 24. This loading and unloading process isrepeated over and over by handling system 21.

[0031] An end effector 28A is present at the end of one arm 26 ofsubstrate handling system 21, and an end effector 28B is attached to theopposing arm 26. Each end effector 28A, 28B includes an inner maskgripper and an outer mask gripper. When handling system 21 rotates, endeffectors 28A and 28B are moved between loadlock 24 and the externaldisk change station. A conventional electric motor 23A rotates and liftsarms 26 and shaft 23.

[0032] The number of arms on substrate handling system 21 can vary. At aminimum, handling system 21 has one arm 26 that supports a single endeffector. FIG. 2 is a simplified top plan view of alternative handlingsystem 21-1 that includes three arms 26, which respectively supportidentical end effectors 28A, 28B, and 28C. When such a system is in use,end effector 28A may be positioned at loadlock 24 (FIG. 1), end effector28B may be at an external station where processed disks are removed fromend effector 28B, and end effector 28C may be at an external stationwhere unprocessed disks are placed on end effector 28C. Rotation ofsubstrate handling system 21-1 moves each arm to the next station. Themethods used at the external disk change station to remove processeddisks from the end effector and to load unprocessed disks onto the endeffector may vary.

[0033] Each end effector 28A, 28B of FIG. 1 includes a lid 32 that islocated vertically between arm 26 and the inner mask gripper and theouter mask gripper. During the loading and unloading process, lid 32 isplaced over opening 24A in loadlock 24. When lid 32 is placed overopening 24A, lid 32 closes the opening and forms a vacuum seal. An0-ring seal may be provided around opening 24A or on lid 32 to help formthe gas tight seal.

[0034]FIG. 3 is a cross-sectional view of a first embodiment of an innermask 42. Inner mask 42 is generally mushroom shaped, and includes anannular head 43 integrally connected to a first end of avertically-extending body 44. Body 44 has tapered sides 46 at anopposite second end of body 44, and an orthogonal portion between head43 and tapered sides 46. Body 44 has a hollow cylindrical aperture 45that begins at the center of annular head 43 and extends vertically intobody 44. While the circumference of aperture 45 is circular in thisembodiment, the shape may vary. The width and depth of central aperture45 are sufficient to allow the gripper fingers of the inner mask gripperto be inserted into aperture 45 and achieve a firm grip on sidewall 45Aof aperture 45. A groove 47 is present around the orthogonal portion ofthe outer surface of body 44 adjacent to aperture 45 and just below head43. A circular steel helical spring 48 is in groove 47 around body 44and extends slightly beyond the sides of body 44.

[0035] An optical disk having a central aperture is captured on innermask 42 by inserting the tapered end of body 44 through the aperture inthe disk. Spring 48 deflects and allows the disk to move upward towardhead 43. Once the disk is past, spring 48 springs back, and captures thedisk under head 43. Head 43 extends over the surface that is to becoated, and thereby masks a central circular portion of the disk duringthe sputtering process.

[0036] Inner mask 42 may be formed from aluminum, steel, or othermaterials. All or part of the upper surface of annular head 43 (which isexposed to direct sputter deposition) has a rough surface that includesmany asperities 49 that can trap sputtered material. Accordingly,material sputtered onto annular head 43 does not fall on and contaminatethe disk. The asperities may be provided by spraying the upper surfaceof annular head 44 with an aluminum ARC spray. The coating gets roughergoing from the outer perimeter of head 43 toward aperture 45.

[0037]FIG. 4 is an exploded view of an alternative inner mask 50.Features similar to inner mask 42 of FIG. 3 have similar referencenumbers. Mask 50 is an assembly of several parts, including a first body51 having a vertically-extending cylindrical portion 51A and an integralannular head 43 with asperities 49 thereon. Cylindrical portion 51A hasa central cylindrical aperture 45 with an inner vertical sidewall 45A. Ascrew hole 52 is at the bottom of cylindrical portion 51A. First body 51is within a hollow second body 53. The outer surface of second body 53includes an orthogonal upper portion 56 and a tapered lower portion 57.A strip 58 of spring steel is between first body 51 and second body 53.A screw 54 extends through a hole 55 in second body 53 and a hole instrip 58 and engages the threads of screw hole 52 of first body 51.Screw 54 thus secures first body 51 to second body 52. Orthogonalportion 56 of second body 53 includes one or more (e.g., two or four)chamfered openings in which a steel ball 59 is held. As a disk passes upsecond body 53, the sidewall of the central aperture of the diskcontacts balls 59 and causes balls 59 to deflect inward. After the diskmoves past balls 59, spring 58 pushes balls 59 outward, which causes thedisk to be captured under head 43.

[0038]FIG. 5 is a cross-sectional side view of a first embodiment of anouter mask 60. Outer mask 60 is formed of aluminum, steel, or anothermaterial.

[0039] Outer mask 60 includes a hollow, vertically-extending body 61.Outer mask 60 is sized so that a disk 22 will fit horizontally withinthe round central aperture 67 of body 61. A lip 62 is at an upper firstend of body 61 and extends inwardly around aperture 67. Lip 62 extendsover a circumferential portion of disk 22, and thereby masks the outerperiphery of disk 22 during the sputtering process. Lip 62 does notcontact the sputtered surface of the disk. The upper surface of lip 62(which is exposed to direct sputter deposition) has numerous asperities49 thereon to catch sputtered material, although asperities 49 may beomitted. A horizontal flange 63 extends outwardly from an outer surfaceof body 61. In one embodiment, flange 63 may be present around theentire outer surface 65 of body 61. In other embodiments, one or more(e.g., four) discrete flanges or other protrusions maybe spaced aroundthe outer surface 65 of body 61. The inner surface of body 61 includes atapered portion 66 adjacent to end 64, where disk 22 enters aperture 67.The inner surface of body 61 also includes a groove 68, which is engagedby a helical spring 41 (FIG. 7) in the tray 39 upon which disk 22 restsduring the sputtering process. The outer mask gripper of the endeffector grips mask 60 on the unsputtered outer surface 65 of body 61beneath flange 63, and may use the lower surface of flange 63 to liftouter mask 60.

[0040]FIG. 6 is a cross-sectional side view of an alternative outer mask69. Most of the features of outer mask 69 are the same as those of outermask 60 of FIG. 5. Instead of having a flange 63, however, outer mask 69has a groove 70 in outer surface 65 that is engaged by the outer maskgripper of the end effector.

[0041]FIG. 7 is a cross-sectional view of a first embodiment of an endeffector 28A (or 28B) of FIG. 1. In this view, end effector 28A ispositioned at loadlock 24 (FIG. 1) so that lid 32 is covering loadlockopening 24A. End effector 28A includes an inner mask gripper 29 and anouter mask gripper 30, the component parts of which are described below.Inner mask gripper 29 is gripping inner mask 42, and outer mask gripper30 is gripping outer mask 60.

[0042] Disk 22 of FIG. 7 is captured and centered on inner mask 42, andis horizontally disposed within outer mask 60. Disk 22 restshorizontally on a metal tray 39, which in turn rests on a verticallymoveable pedestal 27 (FIG. 1). In particular, disk 22 is supported onflat-topped annular protrusions that extend from the top surface of tray39. The protrusions are located near the center of disk 22 and at theperiphery of disk 22, respectively.

[0043] Tray 39 also supports inner masks 42 and outer mask 60. Body 44(FIG. 3) of inner mask 42 is supported in a central aperture in tray 39.Spring 48 (FIG. 3) of inner mask 42 presses against the sidewall of thecentral aperture in tray 39, and thus provides a supportive engagementwith tray 39. Second end 64 (FIG. 4) of outer mask 60 is supported abovean outwardly extending flange 40 of tray 39. A helical spring coil 41 ina groove around tray 39 engages groove 58 (FIG. 5) on the inside surfaceof body 61 of outer mask 60 and applies an outward force, therebysupporting and securing outer mask 60 to tray 39. The metal to metalcontacts between inner mask 42 and outer mask 60, on the one hand, andtray 39 on the other allow heat from the plasma to be conducted frominner mask 42 and outer mask 60 to tray 39, which prevents heat damageto disk 22.

[0044] Pedestal 27 is vertically raised to bring a processed disk 22,tray 39, inner mask 42, and outer mask 60 from the carousel carrier inthe main vacuum chamber to loadlock 24. Pedestal 27 is verticallylowered to bring an unprocessed disk 22, tray 39, inner mask 42, andouter mask 60 to the carousel carrier from loadlock 24.

[0045] Inner mask gripper 29 includes gripper fingers 34 that areinserted into aperture 45 of inner mask 42. Gripper fingers 34 areconnected to gripper arms 33. A linear actuator 31 and a bellows 3 1Acause gripper arms 33 and gripper fingers 34 to move laterally back andforth, as shown by the two headed arrow of FIG. 7. When gripper arms 33are moved apart (the “open” position), gripper fingers 34 push againstinner wall 45A of aperture 45 of inner mask 42 with sufficient force toallow inner mask 42 and disk 22 to be lifted and moved. When gripperfingers 34 are moved together (the “closed” position), inner mask 42 isreleased onto tray 39. Gripper fingers 34 may be threaded to enhancetheir grip on inner mask 42. Inner mask 50 of FIG. 4 maybe used insteadof inner mask 42.

[0046] A feature of inner mask gripper 29 is that inner masks 42 and 50are only gripped on vertically-extending sidewall 45A within aperture45, which is not subjected to direct sputter deposition. Artisans willappreciate that numerous methods may be implemented for gripping theinner mask within central aperture 45.

[0047] Outer mask gripper 30 of FIG. 7 is shown in an enlarged view inFIG. 8. Threads 35 mount outer mask gripper 30 to lid 32. Outer maskgripper 30 includes a rotary actuator 37 that rotates an “L” shaped cam36 that grips outer mask 60 (FIG. 5). When actuator 37 rotates cam 36into the “open” position, the horizontal portion of cam 36 is positionedbeneath flange 63 (FIG. 5) so that outer mask 60 may be lifted by cam36. When actuator 37 rotates cam 36 into a “closed” position, cam 36 ispositioned so that there is no overlap between cam 36 and flange 63,thereby releasing outer mask 60.

[0048] The number of outer mask grippers 30 of end effector 28A mayvary. For example, FIG. 9A is illustrates an end effector 28A havingfour outer mask grippers 30 at 90 degree angles to each other. In analternative embodiment, two or three outer mask grippers 30 may be used.

[0049]FIG. 9B illustrates another embodiment an outer mask gripper 30-1for end effector 28A. In this embodiment, one rotational actuator 37 isused to control three cams 36. The cams 36 are connected by a timingbelt 38 that provides for synchronized motion. The rotation of actuator37 to the “open” position moves each of the cams 36 beneath flange 63 ina coordinated fashion. Inner mask gripper 29 is within timing belt 38.

[0050]FIG. 10 is a simplified view alternative embodiment of endeffector 28A for use with outer mask 69 of FIG. 6. For simplicity, innermask gripper 29 is not shown. In this embodiment, each of four outermask grippers 80 includes a pneumatic actuator, air passage 81 (shown inpart), and bellows 82. When outer mask gripper 80 is in an “open”position, a plunger 83 is moved toward outer mask 69. Plunger 83 movestoward outer mask 69 and engages groove 70 of outer mask 69 (FIG. 6),thereby gripping outer mask 69. When the pneumatic pressure is released,springs 93 in hollow cylindrical body 92 force plunger 83 outward,thereby moving gripper 20 to the “closed” position and releasing outermask 69.

[0051] In FIG. 10, end 64 of outer mask 69 is resting on a flange 85 ofa metal substrate transport tray 84. Tray 84 supports disk 22, innermask 50 and outer mask 69 on the carousel and in the sputteringchambers, similar to tray 39 of FIG. 7. Tray 84 has a central aperturein which inner mask 50 is inserted and supported. Tray 84 is on avertically moveable pedestal 27-1, which is similar to pedestal 27 ofFIG. 7.

[0052]FIG. 11 illustrates pertinent portions of an alternativeembodiment of an end effector 28A. In this embodiment, only a singleactuator and a single feed-through are used to grip both the inner maskand the outer mask. In addition, lid 32-1 is flat, rather than peakedlike lid 32 of FIG. 7.

[0053] In FIG. 11, inner mask gripper 29 is the same as shown in FIG. 7,except that inner mask gripper arm 33 includes a flange 86 that extendsoutwardly from each arm 33. A flexure 88 of steel, spring steel, or thelike is connected between flange 86 and a metal (e.g., steel oraluminum) outer mask gripper 87. Outer mask gripper 87 has roughly a “C”shape and is supported on pin 90. Pin 89 links movement from gripper arm33 and slides and rotates pin 90. Flexure 88 is connected to pin 89.

[0054] When inner mask gripper 29 moves gripper arms 33 and gripperfingers 34 to an “open” position so as to engage inner mask 42, flexure88 moves laterally outward, which causes outer mask gripper 87 to rotatetowards outer surface 65 of outer mask 60 (FIG. 5). A horizontal gripperfinger 91 of outer mask gripper 87 is thereby positioned closely beneathflange 63 of outer mask 60 (FIG. 5) so that outer mask 60 may be liftedby finger 91 of outer mask gripper 87. When inner mask gripper 29 movesgripper arms 33 and gripper fingers 34 to a closed position, flexure 88moves laterally inward, which causes outer mask gripper 87 to be rotatedaway from outer mask 60 so that there is no longer any overlap betweenflange 63 and finger 91, and thereby releases outer mask 60.

[0055] Thus, in the embodiment of FIG. 11, the motion of inner maskgripper 29 is used to cause a gripping of both inner mask 42 and outermask 60. Other ways of borrowing the motion of inner mask gripper 29 togrip outer masks 60 or 69 (FIGS. 5 and 6) will be readily apparent topractitioners of the mechanical arts. Such methods include using cablesand/or linkages. Conversely, the motion of an outer mask gripper 30 ofFIG. 7 could be borrowed to grip inner masks 42 or 50 in alternativeembodiments.

[0056] A feature of the outer mask grippers shown in FIGS. 7 through 11is that outer masks 60 and 69 are only gripped on an outer surface thatis not subject to direct sputter deposition. Artisans will appreciatethat numerous methods may be implemented for gripping the unsputteredportion of the outer mask other than using the example methods shownherein.

[0057] The operation of the substrate handling system 21 of FIG. 1 willbe described with the aid of FIGS. 12a-12 f. FIG. 12a shows substratehandling system 21 in a down position. End effector 28A is located at anexternal disk change station 100. Inner mask 42 and outer mask 60 aregripped (i.e., “open” position) by the inner mask gripper and outer maskgripper, respectively, of end effector 28A. A vacuum system or someother disk loading system at disk change station 30 is used to place anunprocessed disk 22 onto inner mask 42 and within outer mask 60. Whileinner mask 42 and outer mask 60 are at disk changing station 30, and inroute to and from disk changing station 30, masks 42 and 60 are exposedto ambient and therefore can cool.

[0058] Meanwhile, the opposing end effector 28B is located at loadlock24 of sputtering system 20. End effector 28B is not engaged with a disk22, inner mask 42, or outer mask 60, but the carousel of sputteringsystem 20 has been indexed to position a processed optical disk 22,inner mask 42, outer mask 60, and tray 39 beneath end effector 28B. Asmentioned above, inner mask 42, outer mask 60, and tray 39 accompanydisk 22 on the carousel and to the sputtering stations of sputteringsystem 20. The inner mask gripper and outer mask grippers are in a“closed” position. Lid 32 of end effector 28B covers opening 24A ofloadlock 24. FIG. 12b has pedestal 27 of sputtering system 20 (FIG. 1)in up position. Pedestal 27 moves a processed disk 22, masks 42 and 60,and tray 39 to meet loadlock 24 and end effector 28B. Tray 39 also sealsthe lower access to loadlock 24 when pedestal 27 is in its up position,which isolates loadlock 24 from the main vacuum chamber of sputteringsystem 20. After pedestal 27 has risen, loadlock 24 vents to theatmosphere. After the venting is complete or during venting, the innermask gripper and outer mask gripper of end effector 28B are moved totheir respective open positions so that processed inner mask 42 andouter mask 60 are gripped by end effector 28B, thereby capturing disk22A.

[0059]FIG. 12c shows substrate handling system 21 in an up position,which raises end effectors 28A and 28B. End effector 28B is gripping aprocessed disk 22, inner mask 42, and outer mask 60, and end effector28A is gripping an unprocessed disk 22, inner mask 42, and outer mask60. Tray 39 stays in loadlock 24 and pedestal 27 stays up.

[0060] Next, as illustrated in FIG. 12d, substrate handling system 21 isrotated by 180 degrees, thereby locating end effector 28B at disk changestation 100, and end effector 28A at loadlock 24. Pedestal 27 remains inan up position at loadlock 24.

[0061]FIG. 12e shows substrate handling system 21 having returned to adown position. At disk change station 100, the unloading of processeddisk 22 from inner mask 42 of end effector 28B (and the subsequentloading of another unprocessed disk 22 onto inner mask 42 and withinouter mask 60 of end effector 28B) is accomplished by the vacuumapparatus or other mounting system at disk change station 100.

[0062] At loadlock 24 of FIG. 12e, lid 32 of end effector 28A is placedover access opening 24A of loadlock 24 so as to form a vacuum tightseal. End effector 28A pushes inner mask 42 and outer mask 60 onto tray39, securing masks 42 and 60 to tray 39. The inner mask gripper andouter mask gripper are moved to the “closed” position, thereby releasingthe unprocessed disk 22, inner mask 42 and outer mask 60 onto tray 39.Next, loadlock 24 is pumped down to create a vacuum.

[0063]FIG. 12f illustrates processed disk 22 after its separation fromend effector 28B at disk changing station 100. Disk changing station 100subsequently exchanges the processed disk with an unprocessed disk 22.Meanwhile, at loadlock 24, pedestal 27 is lowered through an aperture inthe carousel so that unprocessed disk 22, inner mask 42, outer mask 60,and tray 39 are placed on the carousel system of sputtering system 20.Subsequently, the carousel indexes while the plasma is off. The indexingof the carousel locates another processed disk 22, inner mask 42, outermask 60, and tray 39 under end effector 28A. Whereupon, the cycledescribed above is repeated, so that end effector 28A removes aprocessed disk 22 from loadlock 24, and end effector 28B provides anunprocessed disk 22 to loadlock 24. Substrate handling system 21 iscapable of handling several thousand disks per day.

[0064] The material that is being sputtered onto disk 22 also coats theupper surfaces of annular head 43 of inner mask 42 and lip 62 of outermask 60 (FIGS. 3 and 5). Over time, the edges of annular head 43 andcircular lip 62 become irregular and extended further. The combinedeffect of the deposition on the annular head 43 and circular lip 62 is areduction in coated surface area on the disk and irregularity in thecoated area boundaries. When this deposition or other maintenance issueshave made inner mask 42 and outer mask 60 unusable, they are replaced bya new or refurbished inner mask 42 and outer mask 60. Deteriorated innermask 42 and outer mask 60 are removed at disk change station 100 byclosing the inner mask gripper and outer mask gripper, thereby releasinginner mask 42 and outer mask 60. A new inner mask 42 and outer mask 60are provided for gripping by the end effector. There is no need for aspecial mask change station, nor is there any need for ventingsputtering system 20 to change the masks.

[0065] The embodiments described above are exemplary only. Variationswill be apparent to artisans in view of the above disclosure. Theinvention is limited only by the following claims.

1. A mask for use in a sputtering system wherein a substrate having acentral opening is to be coated with a material, said mask comprising: abody having a central aperture at a first end thereof, said body sizedto be insertable into said central opening in the substrate; and anannular head at the first end of said body around said central aperture,said head extending away from the central aperture.
 2. The mask of claim1 , wherein a surface of the annular head includes numerous asperities,said surface being oriented so as to be exposed to direct sputterdeposition.
 3. The mask of claim 1 , wherein an outer surface of saidbody includes a means for capturing the substrate under said head.
 4. Amask for use in a sputtering system wherein a substrate is to be coatedwith a material, said mask comprising: a hollow body having a centralaperture and a vertically extending sidewall bounding said aperture,said central aperture sized so that the substrate can be horizontallydisposed within said aperture; and a lip at a first end of the bodyaround said central aperture, said lip extending toward said centralaperture.
 5. The mask of claim 4 , wherein the sidewall includes anouter surface, said outer surface having at least one groove therein, 6.The mask of claim 4 , where the sidewall includes an outer surface, andat least one flange extends outwardly from the outer surface.
 7. Themask of claim 4 , wherein a surface of said lip includes numerousasperities, said surface being oriented so as to be exposed to directsputter deposition.
 8. A masking system for use in a sputtering system,wherein a substrate having a central first aperture is to be coated witha material, said masking system assembly comprising: an inner mask andan outer mask; said inner mask including a first body having a centralsecond aperture at a first end thereof, said first body sized to beinsertable into said first aperture in the substrate, and an annularhead at the first end of said first body around said second aperture,said head extending away from the second aperture; and said outer maskincluding a hollow second body having a central third aperture and avertically extending sidewall bounding said third aperture, said thirdaperture sized so that the substrate can be horizontally disposed withinsaid third aperture, and a lip at a first end of the second body aroundsaid third aperture, said lip extending toward said third aperture. 9.The masking system of claim 8 , wherein at least one of said annularhead and said lip include a surface having numerous asperities thereon,said surface being oriented so as to be exposed to direct sputterdeposition.
 10. The masking system of claim 9 , wherein said annularhead and said lip include a surface having numerous asperities thereon,said surface being oriented so as to be exposed to direct sputterdeposition.
 11. A substrate handling system auxiliary to a sputteringsystem, said substrate handling system for handling a substrate, aninner mask for masking a central portion of the substrate, and an outermask for masking a circumferential portion of the substrate, saidsubstrate handling system comprising: an inner mask gripper and an outermask gripper, wherein said inner mask gripper grips the inner mask on asurface thereof that is not subjected to direct sputter deposition, andthe outer mask gripper grips the outer mask on a surface thereof that isnot subjected to direct sputter deposition.
 12. The substrate handlingsystem of claim 11 , further comprising: at least one arm upon which aninner mask gripper and outer mask gripper are mounted; and a lid sizedso as to seal a loadlock opening of said sputtering system when saidinner mask gripper and said outer mask gripper are within said opening.13. The substrate handling system of claim 11 , further comprising anactuator, wherein actuation of said actuator operates both said innermask gripper and said outer mask gripper.
 14. The substrate handlingsystem of claim 11 , further comprising plurality of outer mask grippersfor gripping an outer mask.
 15. The substrate handling system of claim11 , wherein said inner mask gripper includes at least one member thatis adapted to be inserted into an aperture of said inner mask and togrip said inner mask within said aperture.
 16. The substrate handlingsystem of claim 11 , wherein said outer mask gripper includes a memberthat is adapted to engage a groove in the outer mask.
 17. The substratehandling system of claim 11 , wherein the outer mask gripper includes amember that is adapted to contact the outer mask beneath an outwardextension of said outer mask.
 18. A method of handling a substrateassembly in association with a sputtering system, said substrateassembly including a substrate, an inner mask for masking a centralportion of the substrate, and an outer mask for masking acircumferential portion of the substrate, said method comprising:selectively gripping said inner mask on a surface thereof that is notsubjected to direct sputter deposition; and selectively gripping saidouter mask on a surface thereof that is not subjected to direct sputterdeposition.
 19. The method of claim 18 , wherein the inner mask includesa body having a first end and an aperture at said first end, and theinner mask is gripped within said aperture.
 20. The method of claim 18 ,wherein the outer mask includes a hollow body having a verticallyextending sidewall and the outer mask is gripped on an outer surface ofsaid sidewall.
 21. The method of claim 20 , wherein the inner maskincludes a body having a first end and an aperture at said first end,and the inner mask is gripped within said aperture.
 22. The method ofclaim 21 , further comprising using a single actuator to cause thegripping of the inner mask and the outer mask.
 23. The method of claim18 , wherein the inner mask and the outer mask are gripped at aplurality of points.
 24. The method of claim 18 , further comprisingcovering an external opening of a loadlock of the sputtering system. 25.A method of masking a substrate that is to be coated in a sputteringsystem, said substrate having a central first aperture, the methodcomprising: providing an inner mask having a first body with a centralsecond aperture at a first end thereof, said body sized to be insertableinto said first aperture in the substrate, and an annular head at thefirst end of said first body around said second aperture, said headextending away from the central aperture; inserting the first bodythrough said first aperture of the substrate so that a portion of thefirst surface of the disk is superimposed by the annular head.
 26. Themethod of claim 25 , further comprising: providing an outer mask thatincludes a hollow second body having a central third aperture and avertically extending sidewall bounding said third aperture, said thirdaperture sized so that the substrate can be horizontally disposed withinsaid third aperture, and a lip at a first end of the second body aroundsaid third aperture, said lip extending toward said third aperture; andinserting the substrate horizontally into the third aperture of thesecond body so that a peripheral portion of the substrate issuperimposed by the lip.
 27. The method of claim 26 , further comprisingtrapping sputtered material on a surface of at least one of the annularhead and lip that is exposed to direct sputter deposition.
 28. A methodof masking a substrate that is to be coated in a sputtering system, saidmethod comprising: providing an outer mask that includes a hollow bodyhaving a central aperture and a vertically extending sidewall boundingsaid aperture, said aperture sized so that the substrate can behorizontally disposed within said sidewall, and a lip at a first end ofthe body around said aperture, said lip extending toward said aperture;and inserting the substrate horizontally into the aperture of the bodyso that a peripheral portion of the substrate is superimposed by thelip.
 29. A method of sputter coating a substrate, said methodcomprising: positioning a substrate assembly at a sputtering station ina vacuum chamber, wherein said substrate assembly includes a substratehaving a central first aperture, an inner mask, and an outer mask; saidinner mask including a first body having a central second aperture at afirst end thereof, said first body being within said first aperture inthe substrate, and an annular head at the first end of said first bodyaround said second aperture, said head superimposing a surface of thesubstrate; and said outer mask including a hollow second body having acentral third aperture and a vertically extending sidewall bounding saidthird aperture, and a lip at a first end of the second body around saidthird aperture, wherein said substrate is horizontally disposed withinsaid third aperture and said lip superimposes a circumferential portionof said substrate; and sputter depositing material onto the surface ofsubstrate, the annular head, and the lip.
 30. The method of claim 29 ,further comprising trapping sputtered material on a surface of at leastone of the annular head and lip.